Vacuum electron beam welding method for extra-thick double-sided stainless steel composite blank

Abstract

The invention relates to a vacuum electron beam welding method for an extra-thick double-sided stainless steel composite blank. The vacuum electron beam welding method comprises the steps that S1, a blank is prepared; s2, processing the surface of the base material carbon steel; s3, processing the surface of the composite stainless steel; s4, assembling and vacuum electron beam direct welding are carried out twice; s5, performing surface anti-oxidation spraying and packaging treatment on the double-sided composite blank after secondary welding; s6, heating the composite blank in a heating furnace, and rolling; and S7, the composite blank is rolled to the thickness required by the product according to the rolling ratio required by the finished product, and the stainless steel + carbon steel + stainless steel extra-thick double-sided stainless steel composite plate can be obtained after cooling. According to the method, the key technical bottleneck of producing the extra-thick double-sided stainless steel composite blank through the vacuum electron beam welding process is solved, particularly, the influence of vacuum electron beam welding magnetic blowing is eliminated, and powerful technical support can be provided for follow-up variety development and stable production.

Description

Technical Field

[0001] The invention relates to the technical field of composite steel plate manufacturing, in particular to a vacuum electron beam welding method for an extra-thick double-sided stainless steel composite billet. Background Art

[0002] As a new type of material, stainless steel composite plate not only has the advantages of stainless steel such as strong corrosion resistance, good wear resistance, beautiful and durable, easy to form, but also has the good weldability, formability, drawability and thermal conductivity of carbon steel. At the same time, it has low cost, strong adaptability and wide application range. Stainless steel composite plate usually uses stainless steel as the composite layer to ensure the corrosion resistance of the product, and uses carbon steel or alloy steel as the base layer to ensure the strength of the product. The use of stainless steel composite plate can effectively reduce costs by 30% to 50% and save precious metals such as nickel and chromium.

[0003] At present, the traditional process for producing stainless steel composite plates at home and abroad is to use the explosive composite method. The stainless steel-carbon steel composite plates produced by the explosive composite method are mainly single-sided composite, and the production process of extra-thick double-sided stainless steel composite plates is rarely reported. If we consider the principle and process of explosive welding, the double-sided secondary explosive composite is the same as the single-sided explosive composite. However, if we consider the mechanical properties and corrosion resistance of the welding interface, there is a certain explosive welding stress on the interface during the first explosive composite. Therefore, the second double-sided explosive composite will inevitably have a certain impact on the welding quality and interface properties of the first explosive composite interface, and this impact makes it impossible to guarantee the quality of the product. Therefore, the double-sided stainless steel composite plate has always been a technical bottleneck that the traditional explosive composite process cannot break through.

[0004] There are many reports on the production of stainless steel composite billets by traditional vacuum composite welding process, but the traditional process adopts the frame or side strip cladding assembly welding method. This method clads the stainless steel inside the frame for cladding welding. It is a traditional process for producing single-sided stainless steel composite plates. However, for double-sided extra-thick (≥350mm) stainless steel composite billets, the two pieces of stainless steel are required to be outside the carbon steel plate, and the traditional cladding assembly welding method cannot be used. Therefore, it is necessary to develop a new process to realize the production of extra-thick double-sided stainless steel composite billets. Before this, there have been no similar reports or literature at home and abroad. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is to provide a vacuum electron beam welding method for extra-thick double-sided stainless steel composite billets. By developing a new billet assembly + vacuum electron beam welding method, stable production of extra-thick double-sided stainless steel composite billet products can be achieved.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A vacuum electron beam welding method for a super-thick double-sided stainless steel composite blank proposed by the present invention includes the following steps:

[0008] S1. Blank preparation: Select a carbon steel as the base material and two pickled stainless steels as the clad materials. Milling and grinding the base material carbon steel and the clad material stainless steel into blanks with the same length and width dimensions;

[0009] S2. Surface processing of the base material carbon steel: Milling and grinding the upper and lower surfaces of the carbon steel to mill out a metallic luster;

[0010] S3. Surface processing of the clad material stainless steel: Squaring the clad material stainless steel to ensure that the dimensional deviation after processing is ≤2 mm, and grinding and cleaning the surface;

[0011] S4. Grouping the blanks and vacuum electron beam welding are carried out in two times;

[0012] S5. Spraying anti-oxidation on the surface of the double-sided composite blank after secondary welding and carrying out packaging treatment;

[0013] S6. Entering a heating furnace for heating and rolling the composite blank;

[0014] S7. Rolling the composite blank to the product required thickness according to the rolling ratio required by the finished product, and the super-thick double-sided stainless steel composite plate of stainless steel + carbon steel + stainless steel can be obtained after cooling.

[0015] Further, in the step S1, the thickness of the carbon steel is 350-500 mm; the thickness of the pickled stainless steel is 10-50 mm.

[0016] Further, in the step S2, the roughness Ra of the upper and lower surfaces of the carbon steel after milling and grinding is <5 μm.

[0017] Further, in the step S3, the flatness of the processed stainless steel surface is ≤3 mm / m, and the roughness Ra is <5.5 μm.

[0018] Further, the step S4 specifically includes:

[0019] S4.1. First, align and group one side of the carbon steel base material blank with a clad material stainless steel blank, and adopt the following steps:

[0020] S4.1.1. Place the base material blank and the clad material stainless steel on a blank pad with a height of 500-800 mm. Grind the bonding surface of the base material and the clad material until all fresh metals are visible. Before combination after grinding, wipe the bonding surface with a white cloth dipped in alcohol, and then place the stainless steel on the base material to complete the grouping by controlling the alignment;

[0021] S4.1.2. Place a slab on the upper part of the assembled blank for compacting the blank, and use a lifting device to press it tightly above to ensure that the gap between the base material and the composite material is no more than 0.5 mm. Then, clean the gap again with a white cloth dipped in alcohol.

[0022] S4.1.3. Spot-weld the gap on the joint surface of the base material and the composite material by argon arc welding, welding one point every 150 - 250 mm, and perform spot welding on all four sides.

[0023] S4.1.4. After spot welding, use thin steel strips to perform spot welding connections between the compacted blank and the base blank, and the connection requirement is 2 - 4 strips on each side.

[0024] S4.1.5. Place the spot-welded composite blank on the turntable in the vacuum electron beam welding chamber for positioning. When positioning, press a continuous casting blank with dimensions equivalent to the composite blank on the upper part. After positioning, clean the weld seam again with a white cloth dipped in alcohol.

[0025] S4.1.6. Set the vacuum electron beam welding program and perform welding using the continuous welding process.

[0026] S4.2. Second blank assembly and welding. Turn over the welded composite blank and repeat the steps S4.1.1 - S4.1.6 of the first blank assembly and welding.

[0027] Further, in the step S4.1.1, the surface of the base material joint surface after grinding is required to be free of oxides, oil stains, dust, and visible defects.

[0028] Further, in the step S4.1.1, the white cloth after wiping the joint surface does not change color, ensuring that the joint surface is free of oil stains, rust stains, and dust.

[0029] Further, in the step S4.1.3, the requirements for spot welding are: set a spot weld every 150 - 250 mm, the length of the weld is 100 - 150 mm, and the welding penetration depth is 3 - 5 mm.

[0030] Further, in the step S4.1.6, the welding principle is: weld the short sides first and then the long sides, the welding current is 300 - 400 mA, and the welding speed is 6 - 8 mm / s.

[0031] The present invention has the following beneficial effects compared with the prior art:

[0032] The present invention provides a vacuum electron beam welding method for extra-thick double-sided stainless steel composite billets, which not only breaks through the limitation that traditional explosive composite processes cannot produce extra-thick double-sided stainless steel composite plates, but also solves the technical bottleneck that traditional vacuum electron beams cannot directly weld stainless steel and steel due to magnetic blowout. It has taken the lead in realizing the stable production of extra-thick double-sided stainless steel in China, providing strong technical support for the application of stainless steel composite plates in major engineering fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic flow chart of a vacuum electron beam welding method for an extra-thick double-sided stainless steel composite billet proposed by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or in the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0035] A vacuum electron beam welding method for an extra-thick double-sided stainless steel composite billet proposed by the present invention specifically includes the following steps:

[0036] S1. Blank preparation: Select a carbon steel with a thickness of 350 - 500 mm as the base material, select two pickled stainless steels with a thickness of 10 - 50 mm as the clad materials, and mill and process the base material carbon steel and the clad material stainless steel into blanks with the same length and width dimensions.

[0037] S2. Surface processing of the base material carbon steel: Mill the upper and lower surfaces of the carbon steel to produce a metallic luster, and the surface roughness Ra after milling < 5 μm.

[0038] S3. Surface processing of the clad material stainless steel: Square the clad material stainless steel to ensure that the dimensional deviation after processing ≤ 2 mm, and polish and clean the surface. The surface of the processed clad material stainless steel is flat and defect-free, the flatness ≤ 3 mm / m, and the surface roughness Ra < 5.5 μm.

[0039] S4. Blank assembly and welding: Since stainless steel needs to be welded on both sides of the base material and the stainless steel is relatively thin, there are a series of uncontrollable factors such as easy deformation during the welding process and serious magnetic blowout of the electron beam. Therefore, the present invention proposes to carry out blank assembly and welding in two steps.

[0040] S4.1 First blank assembly and welding;

[0041] Align and assemble one side of the base material blank with a piece of clad material stainless steel first. The specific steps are as follows:

[0042] S4.1.1. Place the base material blank and the composite stainless steel on a blank pad with a height of 500 - 800 mm. Grind the bonding surfaces of the base material and the composite material until fresh metal is fully exposed, ensuring that the surface of the ground bonding surface of the base material has no oxides, oil stains, dust, and other visible defects. Before combination after grinding, wipe the bonding surface with a white cloth dipped in alcohol. The white cloth remains unchanged after wiping, ensuring that the bonding surface has no oil stains, rust stains, and dust. Then, use a vacuum chuck to place the stainless steel on the base material and complete the blank assembly by centering control;

[0043] S4.1.2. Place a slab on the upper part of the assembled blank for blank pressing, and use a lifting tool to press it tightly from above to ensure that the gap between the base material and the composite material is not greater than 0.5 mm. Then, clean the gap again with a white cloth dipped in alcohol;

[0044] S4.1.3. Use argon arc welding to spot - weld the gaps on the bonding surfaces of the base material and the composite material. Spot - weld all four sides. Spot - welding requirements: Set a spot - weld every 150 - 250 mm, the length of the spot - weld is 100 - 150 mm, and the welding penetration depth is 3 - 5 mm;

[0045] S4.1.4. Innovatively propose a method of spot - welding thin steel strips to eliminate the influence of welding magnetic blow - out. That is, after spot - welding, use thin steel strips to connect by spot - welding between the pressed blank and the base blank. The connection requirement is 2 - 4 strips on each side. The purpose is to eliminate the interference of the electric field and magnetic field during the vacuum electron beam welding process, avoid magnetic blow - out during the vacuum electron beam welding process, and ensure the welding quality;

[0046] S4.1.5. Place the spot - welded composite blank on the turntable in the vacuum electron beam welding chamber for positioning. When positioning, place a continuous casting blank with the same size as the composite blank on the upper part to prevent welding deformation. After positioning, clean the weld seam again with a white cloth dipped in alcohol;

[0047] S4.1.6. Set the vacuum electron beam welding program and use a continuous welding process for welding. Welding principle: Weld the short sides first and then the long sides. The welding current is 300 - 400 mA, and the welding speed is 6 - 8 mm / s;

[0048] S4.2. Second blank assembly and welding. Turn over the welded composite blank and repeat the steps S4.1.1 - S4.1.6 of the first blank assembly and welding;

[0049] S5. Spray anti - oxidation coating on the surface of the double - sided composite blank after secondary welding and perform packaging treatment;

[0050] S6. Put it into the heating furnace for heating and rolling of the composite blank;

[0051] S7. Roll the composite blank to the required product thickness according to the rolling ratio required for the finished product. After cooling, a super-thick double-sided stainless steel composite plate of stainless steel + carbon steel + stainless steel can be obtained.

[0052] The following further illustrates the present invention through specific examples:

[0053] Prepare a double-sided stainless steel super-thick composite plate with the material of 304 + Q345D + 304. The thickness of the finished product after rolling is 6 + 130 + 8 mm. The specific implementation plan is as follows:

[0054] S1. Blank preparation: Select a Q345D steel blank with a thickness of 400 mm as the base material, and perform milling and grinding on it. The processed size is 390×2000×3000 mm; Select two pickled stainless steels (with thicknesses of 18 mm and 24 mm respectively) as the clad materials, and the sizes are 18×2000×3000 mm and 24×2000×3000 mm respectively;

[0055] S2. Surface processing of the base material Q345D steel blank: Mill the upper and lower surfaces of the Q345D steel blank to produce a metallic luster, and the roughness Ra after milling < 5 μm;

[0056] S3. Surface processing of the clad material 304 stainless steel: Perform sizing processing on the 304 stainless steel to ensure that the dimensional deviation after processing ≤ 2 mm, and polish and clean the surface. The surface of the clad stainless steel after cleaning is flat and defect-free; The final requirement is to meet the flatness ≤ 3 mm / m and the roughness Ra < 5.5 μm;

[0057] S4. Blank assembling and welding: Since stainless steel needs to be welded on both sides of the base material and the stainless steel is relatively thin, there are a series of uncontrollable factors such as easy deformation and serious electron beam deviation during the welding process. The present invention proposes to perform blank assembling and welding in two times.

[0058] S4.1 First blank assembling and welding, align and assemble the Q345D steel with the 24-mm-thick stainless steel first.

[0059] S4.1.1. Place the Q345D steel on a blank pad with a height of 600 mm, grind the bonding surface of the base material and the clad material until all fresh metal is visible, and wipe the bonding surface with a white cloth dipped in alcohol before combination. The wiped rag does not change color, ensuring that the bonding surface has no any oil stain, rust stain and dust. Then place the 304 stainless steel on the base material by using a vacuum chuck, and complete blank assembling by controlling alignment;

[0060] S4.1.2. Place a slab on the upper part of the assembled blank for pressing the blank, and use a lifting tool to press it tightly from above to ensure that the weld between the Q345D steel base blank and the 304 stainless steel clad material is not greater than 0.5 mm. Then clean the weld again with a white cloth dipped in alcohol;

[0061] S4.1.3. Spot weld the gaps on the joint surface of the base material and the clad material by argon arc welding. Spot weld all four sides. Spot welding requirements: Set a spot weld every 150 - 250 mm, the length of the weld is 100 - 150 mm, and the welding penetration depth is 3 - 5 mm;

[0062] S4.1.4. After spot welding, use thin steel strips to make spot weld connections between the compacted blank and the Q345D steel base blank. The connection requirement is 3 thin steel strips on each side. The purpose is to eliminate the interference of the electric field and magnetic field during the vacuum electron beam welding process, avoid magnetic blow - by during the vacuum electron beam welding process, and ensure the welding quality;

[0063] S4.1.5. Place the spot - welded composite blank on the turntable in the vacuum electron beam welding machine chamber for positioning. When positioning, press a continuous casting blank with a size smaller than the composite blank on the upper part. The purpose is to prevent welding deformation. After positioning, clean the weld seam again with a white cloth dipped in alcohol to ensure that the white cloth does not change color;

[0064] S4.1.6. Set the vacuum electron beam welding program and perform welding using the continuous welding process. Welding principle: First weld the short sides and then the long sides. The welding current is 350 mA and the welding speed is 7 mm / s;

[0065] S4.2 Second billet assembly and welding. Turn over the welded composite blank and repeat the steps S4.1.1 - S4.1.6 of the first billet assembly and welding to complete the billet assembly and welding of another 18 - mm - thick stainless steel plate;

[0066] S5. Perform surface anti - oxidation spraying and packaging treatment on the double - sided composite blank after secondary welding;

[0067] S6. Put it into a heating furnace for heating the composite blank;

[0068] S7. Roll the composite blank using the special rolling system for rolling stainless steel, and the rolling ratio is 3. After rolling and cooling, a super - thick double - sided stainless steel composite plate of 144(6 + 130 + 8)×2000×9000 mm can be obtained.

[0069] A vacuum electron beam welding method for a super - thick double - sided stainless steel composite blank proposed by the present invention first proposes to eliminate the influence of magnetic blow - by in vacuum electron beam welding by spot - welding thin steel strips. Through the combination of manual spot - welding and vacuum electron beam welding, it can not only break through the limitation that traditional explosive cladding cannot produce super - thick double - sided stainless steel composite plates, but also solve the technical bottleneck that traditional vacuum electron beam cannot directly weld stainless steel and steel due to the influence of magnetic blow - by. It has taken the lead in realizing the stable production of super - thick double - sided stainless steel in China, providing a strong technical guarantee for the application of stainless steel composite plates in major engineering fields.

[0070] Matters not elaborated in this invention are all well-known technologies.

[0071] The embodiments described above are only used to describe the preferred embodiments of the present invention and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A vacuum electron beam welding method for extra-thick double-sided stainless steel composite billet, characterized in that: The method comprises the following steps: S1. Billet preparation: Select a piece of carbon steel as the base material, select two pieces of pickled stainless steel as the composite material, and mill the base carbon steel and the composite stainless steel into billets with the same length and width; S2. Surface processing of the base carbon steel: milling the upper and lower surfaces of the carbon steel to produce a metallic luster; S3. Surface processing of composite stainless steel: square the composite stainless steel to ensure that the size deviation after processing is ≤2mm, and polish and clean the surface; S4, performing assembly and vacuum electron beam welding in two steps; S5. Anti-oxidation spraying is performed on the surface of the double-sided composite billet after secondary welding and packaging is performed; S6, entering the heating furnace to heat the composite billet and then rolling; S7. Roll the composite billet to the required thickness of the product according to the rolling ratio required by the finished product, and after cooling, obtain an extra-thick double-sided stainless steel composite plate of stainless steel + carbon steel + stainless steel.

2. The vacuum electron beam welding method for extra-thick double-sided stainless steel composite billet according to claim 1, characterized in that: In step S1, the thickness of the carbon steel is 350-500 mm; the thickness of the pickled stainless steel is 10-50 mm.

3. The vacuum electron beam welding method for extra-thick double-sided stainless steel composite billet according to claim 1, characterized in that: In the step S2, the roughness Ra of the upper and lower surfaces of the carbon steel after milling is less than 5 μm.

4. The vacuum electron beam welding method for extra-thick double-sided stainless steel composite billet according to claim 1, characterized in that: In the step S3, the surface roughness of the processed stainless steel is ≤3 mm / m, and the roughness Ra is <5.5 μm.

5. The vacuum electron beam welding method for extra-thick double-sided stainless steel composite billet according to claim 1, characterized in that: The step S4 specifically includes: S4.

1. Align and assemble one side of the carbon steel substrate blank with a composite stainless steel blank in the following steps: S4.1.

1. Place the substrate blank and composite stainless steel on a blank pad with a height of 500-800mm, grind the bonding surface of the substrate and the composite material until fresh metal is visible, and wipe the bonding surface with a white cloth dipped in alcohol after grinding and before assembly. Then place the stainless steel on the substrate and complete the assembly by centering control; S4.1.

2. Place a slab on top of the assembled blank to press it, and use a hanger to press it tightly, ensuring that the gap between the base material and the composite material is no larger than 0.5mm, and then clean the gap again with a white cloth dipped in alcohol; S4.1.

3. Use argon arc welding to spot weld the gap between the substrate and the composite material, welding one point every 150-250mm, and spot welding all four edges; S4.1.

4. After spot welding, spot weld the pressed blank and the base blank with thin steel strips. The connection requirement is 2-4 strips on each side. S4.1.

5. Place the spot-welded composite billet on the rotary table of the vacuum electron beam welding machine room for positioning. During positioning, a continuous casting billet of the same size as the composite billet needs to be pressed on the upper part. After positioning, clean the weld again with a white cloth dipped in alcohol; S4.1.

6. Set the vacuum electron beam welding procedure and use the continuous welding process for welding; S4.2, second assembly and welding, turn over the welded composite billet, and repeat the first assembly and welding steps S4.1.1-S4.1.

6.

6. The vacuum electron beam welding method for extra-thick double-sided stainless steel composite billet according to claim 5, characterized in that: In step S4.1.1, the polished surface of the substrate bonding surface is required to be free of oxides, oil stains, dust and visible defects.

7. The vacuum electron beam welding method for extra-thick double-sided stainless steel composite billet according to claim 5, characterized in that: In the step S4.1.1, the white cloth does not change color after wiping the bonding surface, ensuring that the bonding surface is free of oil, rust and dust.

8. The vacuum electron beam welding method for extra-thick double-sided stainless steel composite billet according to claim 5, characterized in that: In step S4.1.3, the spot welding requirements are: a spot welding point is set every 150-250 mm, the welding point length is 100-150 mm, and the welding penetration is 3-5 mm.

9. The vacuum electron beam welding method for extra-thick double-sided stainless steel composite billet according to claim 5, characterized in that: In step S4.1.6, the welding principle is: short side first and long side later, the welding current is 300-400mA, and the welding speed is 6-8mm / s.

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